A motor-vehicle seat, for example usable in a bus, has a seat part with a generally horizontal sitting surface and a back part extending upward from a rear end of the sitting surface and forming a back-support surface directed forward in a normal vehicle travel direction. Normally the upper portion of the back is provided with or forms a headrest having a front surface that the user can rest his or her head against and that acts as a rearward restraint in an accident. This headrest is often vertically shiftable and/or tippable about a horizontal axis to accommodate users of different height.
U.S. Pat. No. 4,883,243 of Herndon describes an ejection seat for an airplane whose back part has an upper end that forms a headrest as described above. The front surface of this headrest, however, can slide or pivot backward in an emergency so as to greatly increase the front-to-back depth of a cavity of the headrest and cradle the user's head during a forceful ejection procedure. Such a seat is basically unrelated to a seat used in, for instance, a bus.